A method of producing a telescopic cover and a telescopic cover are the subject matter of the earlier application PCT/EP 89/00244 by the applicant. This prior art is explained in detail with the aid of FIGS. 1 to 3 in the description. In this method, during production of the diamond-shaped cut-out in the flat sheet material blank the material zone between the diamond-shaped cut-out and the adjacent outer end (which in the finished telescopic cover runs at right angles to the longitudinal direction of the cover) of the sheet material blank is separated by a stamped cut, so that the sections of the end region located on different sides of this stamped cut can move together with the top wall and the adjoining side wall freely relative to one another during bending of the sheet material blank. Thus this method results in a cover in which the end region which projects outwards over the top wall and the side walls has a right-angled cut-out in the two corner zones which must then be closed again in a separate operation (for instance by welding) in order to produce the necessary sealing of the cover element in the corner zones of the end region.